She wants a ban on the machinery which made the bullets used to kill her son.

Mr Wood raised the matter with Tony Blair in the Commons during Prime Minister's Question Time.

Mr Wood said: "The Prime Minister will know that my constituent police constable Ian Broadhurst was shot dead in Leeds on Boxing Day last year. It now transpires that the bullets that were used in that killing and in the attempted murder of two colleagues were home made.

"The components and the machine necessary to produce that ammunition were bought over the counter, with no questions, no vetting and apparently no checks whatever.

"Will my right honourable friend pledge his and his Government's support to the campaign launched by Pc Broadhurst's mother Cindy Eaton to have this loophole in the law closed and quickly?"

Mr Blair, who again extended his sympathies to Pc Broadhurst's family, told Mr Wood: "We are studying very carefully not just the facts of this particular case but also the campaign on behalf of the family and we hope to make a response shortly.

"I entirely agree that the particular issue of the way these things are sold over the counter is a very important issue.